Electronic devices having complementary dual displays

ABSTRACT

Methods for controlling complementary dual displays for use with an electronic device are presented including: sending a video signal to a first display, wherein the first display is a refresh-based, high frame rate display; displaying the video signal on the first display; and printing a frame of the video signal to a second display, wherein the second display is a bistable, low frame rate display, the printing including, loading a portion of a current frame of the video signal into a frame buffer, and displaying the current frame of the video signal to a second display, such that a bistable static image is displayed on the second display.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation-in-Part of co-pending U.S.patent application Ser. No. 11/602,539, entitled, “METHODS FORCONTROLLING COMPLEMENTARY DUAL DISPLAYS,” filed on Nov. 20, 2006, whichis incorporated herein by reference.

The present application is related to the following application, whichis incorporated herein by reference: Commonly assigned U.S. patentapplication Ser. No. 11/702,789 entitled “ELECTRONIC DEVICES HAVINGCOMPLEMENTARY BISTABLE AND REFRESH-BASED DISPLAYS,” filed on even dateherewith by the same inventors herein.

PRIORITY CLAIM TO PROVISIONAL APPLICATION

A claim for priority is hereby made under the provisions of 35 U.S.C.§119 for the present application based upon U.S. Provisional ApplicationNo. 60/848,538, filed on Sep. 29, 2006, which is incorporated herein byreference; upon U.S. Provisional Application No. 60/844,979, filed onSep. 14, 2006, which is incorporated herein by reference; and upon U.S.Provisional Application No. 60/850,013 filed on Oct. 6, 2006, which isincorporated herein by reference.

BACKGROUND

LCD-based electronic devices such as Ultra Mobile PC (UMPC),laptops/PCs, personal digital assistants (PDAs), cellular phones,portable digital media players, and the like are becoming ubiquitous inmodern technological societies. These devices offer specializedfunctionality in form factors small enough to carry in a pocket or someother small carrying bag. At least one reason why these types of devicesare so popular is because display technology, which provides aconvenient user interface, has advanced to a point where relativelysmall form factors are efficient and inexpensive. Indeed, even the mostinexpensive portable electronic devices now include high frame ratecolor displays. However, conventional displays are not without somedisadvantages.

Typically, a PDA may include a refresh-based, high frequency (REHF)display for displaying user selected information. One example of an REHFdisplay is a liquid crystal display (LCD). LCDs have many desirablecharacteristics including high frame rates which provide for asatisfying visual experience when rapidly switching between screens orwhen scrolling across a screen. However, typical displays having highscreen refresh rates may suffer from poor readability becausebacklights, which are required in those displays, may be adverselyaffected by ambient lighting conditions. Eye strain is commonly reportedby users and has been documented in some medical literature. Users ofUMPCs or PDAs are familiar with the poor readability of LCDs underbright light or direct sunlight. In some examples, shading the screen ormoving to a darker environment may be necessary to read an LCD.

In order to overcome the shortcomings of an LCD, bistable, low frequency(BILF) displays may be utilized instead of an LCD. One example of a BILFdisplay is and electronic paper display (EPD). EPDs utilize a materialcalled electronic ink and are commercially available under the tradename E INK®. EPDs are ideally suited for flexible display applicationsdue to their thin form factor and inherent flexibility. EPDs provide animage stable reflective display technology that uses ultra-low power butis easily read under any lighting condition including direct sunlight.In addition, EPDs provide a bistable display and unlike LCDs, an imageon an EPD looks the same from all viewing angles. Further, EPDs will notdistort when touched or flexed, making EPDs the ideal display medium forflexible displays and portable devices. EPDs however, cannot, in manyexamples, completely replace LCDs. At least one reason is because EPDstypically have a low frame rate. As noted above, conventional LCDs aretypically configured with high frame rates, which may serve to enhance auser's viewing experience especially when rapidly scrolling throughmultiple displays. In addition, using a mouse requires high frame ratesso that the mouse pointer appears to have smooth movement across ascreen. Furthermore, currently, a majority of reading content is createdfor viewing with an REHL display application such as an LCD applicationwhile few applications are written for BILF displays such as an EPD.This trend is likely to continue. It may, therefore, be advantageous toeasily display the output of existing REHF display applications on BILFdisplays such as an EPD.

It may, therefore, be desirable to provide a complementary display toconventional portable electronic device or desktop PC displays whichprovide a highly readable display that overcomes harsh ambient lightconditions, reduces eye strains and does not overly diminish batterylife. The method and the heterogeneous display hardware design candeliver many new classes of EPD usage models, including: (1) thecapability to extend (or migrate) an REHF-based application to a BILFdisplay for better reading experience where a user may also browse thepages on BILF display without changing the application (in this example,a BILF display could be tightly integrated with an REHF display throughsystem bus or loosely linked through an external device); and (2) theability to create dual-display aware applications that can takeadvantages of the unique benefits of both BILF and REHF displays at thesame time. These methods can enable extreme ease-of-use involving twoheterogeneous displays without traditional “file synch” model thatrequires multiple steps of selecting files, transfer files and thenopening files and then browsing to the desired page. As such, methodsfor controlling complementary bistable and refresh-based displays areprovided herein.

SUMMARY

The following presents a simplified summary of some embodiments of theinvention in order to provide a basic understanding of the invention.This summary is not an extensive overview of the invention. It is notintended to identify key/critical elements of the invention or todelineate the scope of the invention. Its sole purpose is to presentsome embodiments of the invention in a simplified form as a prelude tothe more detailed description that is presented below.

Therefore, methods for controlling complementary dual displays for usewith an electronic device are presented including: sending a videosignal to a first display, wherein the first display is a refresh-based,high frame rate display; displaying the video signal on the firstdisplay; and printing a frame of the video signal to a second display,wherein the second display is a bistable, low frame rate display, theprinting including, loading a portion of a current frame of the videosignal into a frame buffer, and displaying the current frame of thevideo signal to a second display, such that a high resolution staticimage is displayed on the second display. In some embodiments, methodsfurther include: loading a zoom buffer, the zoom buffer populated with anumber of enlarged zoom frames and a number of reduced zoom frames basedon the current frame; and selecting a zoom frame for display on thesecond display. In some embodiments, methods further include: on a pancommand for the second display, determining whether a displayed frame isthe zoom frame displayed on the second display that is one of the numberof enlarged zoom frames; if the displayed frame is the zoom framedisplayed on the second display that is one of the number of enlargedzoom frames, displaying the zoom frame that corresponds with the pancommand, else selecting a panned page from the first display andprinting the panned page on the second display. In some embodiments,methods further include: loading a composite buffer with a compositeframe, the composite frame representing a composite image of at leasttwo frames stored in the frame buffer.

In other embodiments, methods for controlling complementary dualdisplays for use with an electronic device are presented including:sending a first video signal to a first display wherein the firstdisplay is a refresh-based high frame rate display; displaying the firstvideo signal on the first display; sending a second video signal to asecond display wherein the second display is a bistable low frame ratedisplay; and displaying the second video signal on the second display atthe low frame rate. In some embodiments, the second video signal is sentover a wireless connection to an external second display with a readingcard and the reading card can send page up/down commands back to readthe content from the application resided at the device of the firstdisplay. In some embodiments, methods further include: on a cleancommand for the second display, refreshing a current frame such thatartifacts are reduced. In some embodiments, on a wipe command for thesecond display, wiping the second display such that the second displayis blank. In some embodiments, the second video signal includes statusinformation, wherein the status information is selected from the groupconsisting of: power information, network connection information, signalstrength information, user configuration information, displaywakefulness information, date information, time information, applicationinformation, and system information.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example, and not by wayof limitation, in the figures of the accompanying drawings and in whichlike reference numerals refer to similar elements and in which:

FIG. 1 is an illustrative flowchart for printing to a bistable, lowfrequency (BILF) display in accordance with embodiments of the presentinvention;

FIG. 2 is an illustrative flowchart for migrating a display between aBILF and a REHF display in accordance with embodiments of the presentinvention;

FIG. 3 is an illustrative representation of a number of zooms and a zoombuffer in accordance with embodiments of the present invention;

FIG. 4 is an illustrative flowchart for zooming on a BILF display inaccordance with embodiments of the present invention;

FIG. 5 is an illustrative flowchart for panning on a BILF display inaccordance with embodiments of the present invention;

FIG. 6 is an illustrative flowchart for paging up and down on a BILFdisplay in accordance with embodiments of the present invention;

FIG. 7 is an illustrative flowchart for flipping an image on a BILFdisplay in accordance with embodiments of the present invention;

FIG. 8 is an illustrative representation of a portion of an electronicpaper display (EPD) having a number of artifacts in accordance withembodiments of the present invention;

FIG. 9 is an illustrative flowchart for cleaning artifacts on a BILFdisplay in accordance with embodiments of the present invention; and

FIG. 10 is an illustrative flowchart for cycling a REHF display beingutilized in connection with a BILF display in accordance withembodiments of the present invention.

DETAILED DESCRIPTION

The present invention will now be described in detail with reference toa few embodiments thereof as illustrated in the accompanying drawings.In the following description, numerous specific details are set forth inorder to provide a thorough understanding of the present invention. Itwill be apparent, however, to one skilled in the art, that the presentinvention may be practiced without some or all of these specificdetails. In other instances, well known process steps and/or structureshave not been described in detail in order to not unnecessarily obscurethe present invention.

Various embodiments are described hereinbelow, including methods andtechniques. It should be kept in mind that the invention might alsocover articles of manufacture that includes a computer readable mediumon which computer-readable instructions for carrying out embodiments ofthe inventive technique are stored. The computer readable medium mayinclude, for example, semiconductor, magnetic, opto-magnetic, optical,or other forms of computer readable medium for storing computer readablecode. Further, the invention may also cover apparatuses for practicingembodiments of the invention. Such apparatus may include circuits,dedicated and/or programmable, to carry out tasks pertaining toembodiments of the invention. Examples of such apparatus include ageneral-purpose computer and/or a dedicated computing device whenappropriately programmed and may include a combination of acomputer/computing device and dedicated/programmable circuits adaptedfor the various tasks pertaining to embodiments of the invention.

FIG. 1 is an illustrative flowchart 100 for printing to a bistable, lowfrequency (BILF) display in accordance with embodiments of the presentinvention. At a first step 102, the method determines whether printingto a BILF display is requested. Typically, in a dual display system, anREHF display (i.e. LCD) is utilized to navigate a user interface. Asnoted above, high frame rates provide for a satisfying visual experiencewhen rapidly navigating between screens or when scrolling across ascreen whereas low frame rates may not provide as satisfying anexperience. Thus, the method contemplates that, as an initial condition,an REHF display is in use when printing to a BILF display is requested.If printing is not requested at a step 102, the method ends. If printingis requested at a step 102, the method continues to a step 104 todetermine whether an area selection is desired. As may be appreciated, auser may desire to print only a portion of a currently displayed imageon a REHF display. As such, in some embodiments, a user may select aportion of a displayed image for printing to a BILF display. If an areaselection is desired at a step 104, the method continues to a step 106to select an area for printing whereupon the method continues to a step108. If an area selection is not desired at a step 104, the methodcontinues to a step 108 to determine whether a frame buffer is full.

In some embodiments, a frame buffer may be utilized to store currentlyprinted and previously printed frames. Frame buffers are generallywell-known in the art and may be utilized without limitation withoutdeparting from the present invention. In one embodiment, the framebuffer is configured to store at least four frames, more preferably 5 to10 frames, still more preferably greater than 10 frames. A framerepresents a bistable static image. It may be appreciated that thenumber of frames stored is largely a function of memory capacity. Thatis, in some embodiments, many more frames may be stored withoutdeparting from the present invention. If the method determines, at astep 108, that the frame buffer is full, then the oldest frame in theframe buffer is purged at a step 110. Thus, in some embodiments, framebuffers may be configured as first in first out (FIFO) buffers. Themethod then continues to a step 112. If the method determines, at a step108, that the frame buffer is not full, then the method continues to astep 112 to load the selection or image into the frame buffer. Themethod then populates a zoom buffer at a step 114. Zoom buffers will bediscussed in further detail below for FIGS. 34 below.

The method continues, at a step 116, to populate a composite buffer. Acomposite buffer may be utilized to provide a user with an indication ofwhat resides in a frame buffer. An image representing a composite imageof at least the last two frames stored in the frame buffer may be loadedinto a composite buffer. Each time a new image is selected for printingto a BILF display, a new composite image may be loaded into thecomposite buffer. Furthermore, as may be appreciated, if a frame buffercontains more than four images, more images may be utilized to populatea composite buffer with other composite images in some embodiments.Thus, a part of, or all of a frame buffer may be represented withcomposite images without departing from the present invention.

After the method populates a composite buffer at a step 116, the methodcontinues, at a step 118, to display the frame that was loaded into theframe buffer at a step 112. The method then ends. It may be appreciatedthat printing to a BILF display as contemplated by flowchart 100 resultsin a high static image displayed on the BILF display that was previouslydisplayed and continues to be displayed on an REHF display. A user maythen navigate on the REHF display while maintaining a bistable staticimage on the BILF display. In some embodiments, a user may wish tomigrate an application between a BILF display and an REHF display. Thus,migration may provide for switching either the entire screen or theapplication focus between the BILF and REHF.

FIG. 2 is an illustrative flowchart 200 for migrating a display betweena BILF display and a REHF display in accordance with embodiments of thepresent invention. At a first step 202, an application is beingdisplayed on an REHF display. At a next step 204, the method determineswhether migrating an application to a BILF display is required. Thus,although typically, a user may prefer to navigate an application over aREHF display, there may be instances where it is desirable to navigatean application over a BILF display, such as with a reading applicationfor example. The migration of an REHF-based application to a bistabledisplay tends to enhance reading experience and provides a user with acapability to browse reading pages on the bistable display after themigration. If the method determines, at a step 204, that a migration isnot required, the method continues to a step 202 to continue displayingthe application on an REHF display. If the method determines, at a step204, that a migration is required, the method determines whether a BILFdisplay is powered on. If method determines that the BILF display is notpowered on at a step 206, the method then powers on the BILF display ata step 208. The method then continues to a step 210 to convert the REHFdisplay video signal to a BILF display video signal. In someembodiments, a preview screen may be displayed on an REHF display beforesending to a BILF display. As may be appreciated, resolution, color andframe rate differences must be resolved before migrating a signal to aBILF display. Any number of conversion methods known in the art may beutilized without departing from the present invention. As may beappreciated, video signals sent to the BILF in any manner well-known inthe art without departing from the present invention. Thus, in someembodiments, a wired connection may include: PCMCIA, SDIO, USB, Serial,and DVI. In other embodiments, a wireless connection may include:Bluetooth, 802.11a, 801.11b, 802.11g, 2.4 GHz wireless, IR wireless, andultra wide band.

To illustrate an embodiment employing application migration and screensynch between two complimentary displays, the following steps illustratea usage model that includes a smart-phone configured with an LCD andconnected through Bluetooth link with an EPD device. Both displays areconfigured with similar resolution but the LCD is color and the EPDdevice is monochrome.

Step 1: Begin a reading application (like Microsoft Windows Mobile WORD)on the phone. In this condition, the application displays a firstreading page on the smart-phone LCD while the EPD device remains blank.

Step 2: Press a key (mapped to a migration command) on the smart-phoneside to start a screen-synch session. Migration turns the EPD device onand displays the first reading page on the EPD device in monochrome. Insome examples, a best display color and best display resolution may beautomatically configured upon sensing a type of device. In someexamples, the smart-phone may enter a standby mode to conserve batterypower.

Step 3: Press a key (mapped to a pagination command) on the EPD deviceto page up or down. Paging on the EPD displays a newly navigated page ofthe WORD application running at the smart-phone device. When paging isperformed on the EPD, the smart-phone LCD can synch up immediately(although the newly navigated page may not be visible if the smart-phoneis in a standby mode with the LCD turned off). Zooming a page todifferent font size may be also be accomplished on the EPD device sidevia a key mapped to a zoom command.

Step 4: Press a key (mapped to a search command) to search for a textstring. For smart-phones having search capability, searching for a textstring may be accomplished on the LCD mart-phone side. When a textstring is found, a new page containing the first occurrence of thespecified string may be displayed on the LCD. Meanwhile the EPD devicemay synch up to the same page in a few seconds. Reading may then resumeat the EPD device.

Step 5: Press a key (mapped to a session termination command) to end thescreen-synch session and to close read activity on the EPD device side.The smart-phone maintains the last browsed page on the EPD device priorto invoking the terminate session command.

Optional Configuration: In some embodiments, if the smart-phone includesan integrated EPD display, migration and screen synch operations canoccur between the smart-phone LCD and the integrated EPD display. Thismeans that the smart-phone can select one of the two EPD displays to beits complimentary display. The above examples illustrate methods thatare configured to take advantage of EPD reading advantages on mainstreamapplications that are generally developed for use with an. Additionally,in some embodiments, an application configured to be aware of thepresence of both an LCD and an EPD displays might be enabled to displaydifferent content of the same application on each display. Thus, forexample, an LCD may be selected to display a table of contents of, forexample, the Bible while an EPD may be selected to display the Book ofJohn. Multi-tasking may also be enabled utilizing one (or more) EPDs ina reading session of one application while an attached LCD runs adifferent application each of which may provide access to applicationcommands by selectively pressing a key mapped to a display selectioncommand. Therefore, many configurations as described may be practicedwithout departing from the present invention.

At a next step 212, the method displays and refreshes a BILF display ata rate corresponding with the display rate of the particular BILFdisplay. As may be appreciated, unlike printing to a BILF display,migrating to a BILF display results in a display from which anapplication may be navigated. That is, utilizing methods describedherein, a BILF display may serve a purpose similar to conventional REHFdisplays. In one embodiment, video signals sent to an REHF display andto a BILF display may correspond with a common application. In someembodiments, video signals may correspond with a common screen or withdifferent screens within the common application. Further, in someembodiments, screen commands or menus may be accessed from either anREHF display or a BILF display. Still further, in some embodiments,video signals sent to an REHF display and to a BILF display maycorrespond with different applications. Thus, in some embodiments, auser may navigate one or more applications of REHF and BILF displaysmore or less simultaneously.

FIG. 3 is an illustrative representation of a number of zooms (304, 306,308, and 310) and a zoom buffer 320 in accordance with embodiments ofthe present invention. As illustrated, normal view 302 may be resized toaccommodate any number of zooms. It may be appreciated that zooming, inthis manner, is relevant to printing an image to a BILF display asillustrated in flowchart 100 (see FIG. 1). Thus, in some embodiments, afirst zoom 304 may include four images that may be zoomed to normal sizefor viewing; a second zoom 306 may include nine images that may bezoomed to normal size for viewing; a third zoom 308 may include areduced image; and a fourth zoom 310 may include a further reducedimage. Zooms may include ranges of approximately: 40 to 69%; 70 to 99%;101 to 175%; and 176 to 300% without departing from the presentinvention. As may be appreciated, zooms illustrated are disclosed forclarity in understanding embodiments of the present invention. As such,any number of other zooms may be employed without departing from thepresent invention.

Zoom buffer 320 may be utilized to store all of the zoom frames. In oneembodiment, zoom buffer may be configured to store at least 15 zoomframes. In some embodiments, zoom buffer may be configured to store morethan 15 zoom frames. As may be appreciated, the number of zoom framesstored is directly related to image resolution and storage size. In someembodiments, zoom frames may be displayed sequentially as loaded into azoom buffer. In other embodiments, zoom frames may be displayednon-sequentially. Thus, any method of accessing zoom frames may beutilized without departing from the present invention.

FIG. 4 is an illustrative flowchart 400 for zooming on a BILF display inaccordance with embodiments of the present invention. As noted above,when an image is printed to a BILF display, the image is a bistablestatic image. That is, when printing, an image is captured at a momentin time and is not updated unless a user initiates an update. As such,zooming requires specialized handling to accommodate thischaracteristic. At a step 402, an image is being displayed on a BILFdisplay. At a next step, 404 the method determines whether zooming isrequired. Zooming may be user initiated in any number of mannerswell-known in the art without departing from the present invention. Forexample, in an embodiment, a zoom button embodied in a physical orvirtual interface may serve to provide zoom input. If the methoddetermines at a step 404 that a zooming is not required, the methodends. If the method determines at a step 404 that paging is required,the method determines whether the BILF display is in a migrated mode ata step 406. Migration is discussed in further detail above for FIG. 2.Notably, when a BILF display is in a migrated mode, the displayedapplication is navigable over the BILF display. When a BILF display isnot in a migrated mode, then the displayed image is a static image whichcannot be utilized to navigate an application.

If the method determines at a step 406 that the BILF display is in amigrated mode, then the method calls the application API at a step 412for a requested zoom. The method then prints the zoomed image to theBILF display at a step 414, whereupon the method ends. In a migratedexample, the BILF display is then refreshed at the display frequencyrate. If the method determines at a step 406 that the BILF display isnot in a migrated mode, then the method selects a desired zoom framefrom a zoom buffer at a step 408. As noted above, any number of zoomframes may be selected from a zoom buffer (see FIG. 3). Thus, zoomframes may be selected sequentially or non-sequentially withoutdeparting from the present invention. The method then prints theselected zoom frame from a zoom buffer at a step 410 whereupon themethod ends. In addition to displaying a selected zoom, zoom frames mayalso provide for panning features that would otherwise require a user tore-access an application that is being displayed on a BILF.

FIG. 5 is an illustrative flowchart 500 for panning on a BILF display inaccordance with embodiments of the present invention. As noted above,when an image is printed to a BILF display, the image is a bistablestatic image. That is, when printing, an image is captured at a momentin time and is not updated unless a user initiates an update. As such,panning requires specialized handling to accommodate thischaracteristic. At a step 502, an image is being displayed on a BILFdisplay. At a next step, 504 the method determines whether a pan isrequired. A pan may be user initiated in any number of mannerswell-known in the art without departing from the present invention. Forexample, in an embodiment, a pan button embodied in a physical orvirtual interface may serve to provide panning input. If the methoddetermines at a step 504 that a pan is not required, the method ends. Ifthe method determines at a step 504 that a pan is required, the methoddetermines whether the BILF display is in a migrated mode at a step 506.Migration is discussed in further detail above for FIG. 2. Notably, whena BILF display is in a migrated mode, the displayed application isnavigable over the BILF display. When a BILF display is not in amigrated mode, then the displayed image is a static image which cannotbe utilized to navigate an application.

If the method determines at a step 506 that the BILF display is in amigrated mode, then the method calls the application API at a step 518for an appropriate pan. The method then prints the pan to the BILFdisplay at a step 520 whereupon the method ends. In a migrated example,the BILF display is then refreshed at the display frequency rate. If themethod determines at a step 506 that the BILF display is not in amigrated mode, then the method determines whether the BILF display iscurrently in a zoom mode. That is, whether a zoom frame is currentlybeing displayed. If the method determines at a step 508 that the BILFdisplay is not in a zoom mode, then no pan image is available and themethod continues to a step 518. If the method determines at a step 508that the BILF display is in a zoom mode, then a determination of whethera panned image is available is made at a step 510. As may beappreciated, some zoom frames may not include panned images. Forexample, a zoom frame having a zoom of less than 100% will not includeany panned images. If the method determines at a step 510 that a pan isnot available, then the method the method continues to a step 518. Ifthe method determines at a step 510 that a pan is available, then themethod may print a selected pan (i.e. zoom frame) from the zoom bufferwhereupon the method ends.

FIG. 6 is an illustrative flowchart 600 for paging up and down on a BILFdisplay in accordance with embodiments of the present invention. Asnoted above, when an image is printed to a BILF display, the image is abistable static image. That is, when printing, an image is captured at amoment in time and is not updated unless a user initiates an update. Assuch, paging requires specialized handling to accommodate thischaracteristic. At a step 602, an image is being displayed on a BILFdisplay. At a next step, 604 the method determines whether paging isrequired. Paging may be user initiated in any number of mannerswell-known in the art without departing from the present invention. Forexample, in an embodiment, a paging button embodied in a physical orvirtual interface may serve to provide paging input. If the methoddetermines at a step 604 that a paging is not required, the method ends.If the method determines at a step 604 that paging is required, themethod determines whether the BILF display is in a migrated mode at astep 606. Migration is discussed in further detail above for FIG. 2.Notably, when a BILF display is in a migrated mode, the displayedapplication is navigable over the BILF display. When a BILF display isnot in a migrated mode, then the displayed image is a static image whichcannot be utilized to navigate an application.

If the method determines at a step 606 that the BILF display is in amigrated mode, then the method calls the application API at a step 612for a requested page (i.e. next/last page). The method then prints thepage to the BILF display at a step 614 whereupon the method ends. In amigrated example, the BILF display is then refreshed at the displayfrequency rate. If the method determines at a step 606 that the BILFdisplay is not in a migrated mode, then the method determines whetherthe requested page is present in a frame buffer at a step 608. As notedabove, a frame buffer may be utilized to store a number of frames. Auser may access frames stored in a frame buffer for display. If themethod determines at a step 608 that the requested page is not in aframe buffer, then the method continues to a step 612. If the methoddetermines at a step 608 that the requested page is in a frame buffer,then the method prints the requested page from the frame buffer at astep 610 whereupon the method ends.

FIG. 7 is an illustrative flowchart for flipping an image on a BILFdisplay in accordance with embodiments of the present invention. Asnoted above, when an image is printed to a BILF display, the image is abistable static image. That is, when printing, an image is captured at amoment in time and is not updated unless a user initiates an update. Assuch, flipping requires specialized handling to accommodate thischaracteristic. At a step 702, an image is being displayed on a BILFdisplay. At a next step, 704 the method determines whether flipping isrequired. Flipping may be user initiated in any number of mannerswell-known in the art without departing from the present invention. Forexample, in an embodiment, a flipping button embodied in a physical orvirtual interface may serve to provide flipping input. In someembodiments, flipping may be automated to correspond with a particularscreen position. If the method determines at a step 704 that a flippingis not required, the method ends. If the method determines at a step 704that flipping is required, the method determines whether the BILFdisplay is in a migrated mode at a step 706. Migration is discussed infurther detail above for FIG. 2. Notably, when a BILF display is in amigrated mode, the displayed application is navigable over the BILFdisplay. When a BILF display is not in a migrated mode, then thedisplayed image is a static image which cannot be utilized to navigatean application.

If the method determines at a step 706 that the BILF display is in amigrated mode, then the method calls the application API at a step 712to provide a flipped page. The method then prints the flipped page tothe BILF display at a step 714 whereupon the method ends. In a migratedexample, the BILF display is then refreshed at the display frequencyrate. If the method determines at a step 706 that the BILF display isnot in a migrated mode, then the method flips the current frame andloads a flipped frame of the current frame into a flip buffer at a step708. In some embodiments, the flipped frame is loaded into a framebuffer. The method then prints the flipped frame from a flip buffer at astep 710 whereupon the method ends. Flipping a frame may have advantagesin some portable electronic devices. For example, where a device may beopened to several positions to approximately 360°, flipping an image ona complementary display may provide a more convenient user experience.

FIG. 8 is an illustrative representation of a portion of an electronicpaper display (EPD) 800 having a number of artifacts in accordance withembodiments of the present invention. EPDs utilize a material calledelectronic ink and are commercially available under the trade name EINK®. Electronic ink includes millions of tiny microcapsules 820A and820B, about the diameter of a human hair. In this example, eachmicrocapsule 820A and 820B contains positively charged white particles824A and 824B and negatively charged black particles 822A and 822Bsuspended in a clear fluid 826A and 826B. When a negative electric fieldis applied across top electrode 804 and bottom electrode 808, positivelycharged white particles 824A move to the top of microcapsule 820A wherethey become visible to the user. This makes the surface appear white atthat spot. At the same time, an opposite electric field 812 pulls thenegatively charged black particles 822A to the bottom of microcapsule820A where they are hidden. By reversing this process and applying apositive electric field across top electrode 804 and bottom electrode808, negatively charged black particles 822B appear at the top ofmicrocapsule 820B, which now makes the surface appear dark at that spot.At the same time, an opposite electric field 810 pulls the positivelycharged white particles 824B to the bottom of microcapsule 820B wherethey are hidden. In some instances, some artifacts 828A and 828B mayremain mixed with charged particles 824A and 822B. These artifacts mayresult in ghosting in some images which may render an image difficult orimpossible to read. In order to remove artifacts, an image may cleanedby refreshing a displayed image.

FIG. 9 is an illustrative flowchart 900 for cleaning artifacts on a BILFdisplay in accordance with embodiments of the present invention. At afirst step 902, the method determines whether auto cleaning is enabled.If the method determines that auto cleaning is enabled at a step 902,then the method refreshes each newly printed frame. Refreshing a printedframe (i.e. screen), in some embodiments, may be largely transparent toa user. That is, refreshing a screen may not, in some embodiments, clearthe screen before an image is refreshed. In that example, a user mayexperience only a slight distortion in a displayed image on refresh;viewing would otherwise be unaffected. In other embodiments, the screenmay be cleared before refresh. The method then continues to a step 906.If the method determines at a step 902 that auto cleaning is notenabled, the method continues to a step 906 to determine whether a userinitiated clean is requested. A user may, in some embodiments, request acleaning where artifacts have resulted in poor readability. Cleaning maybe user initiated in any number of manners well-known in the art withoutdeparting from the present invention. For example, in an embodiment, acleaning button embodied in a physical or virtual interface may serve toprovide cleaning input. If the method determines at a step 906 that auser clean is requested, then the method refreshes the displayed frameat a step 908 whereupon the method ends. As noted above, refreshing aprinted frame, in some embodiments, is largely transparent to a user.That is, refreshing a screen may not, in some embodiments, clear thescreen before an image is refreshed. In that example, a user mayexperience only a slight distortion in a displayed image on refresh;viewing would otherwise be unaffected. In other embodiments, the screenmay be cleared before refresh. If the method determines at a step 906that a user clean is not requested, then the method ends.

FIG. 10 is an illustrative flowchart 1000 for cycling a REHF displaybeing utilized in connection with a BILF display in accordance withembodiments of the present invention. Because some BILF displays includesome power savings advantages, it may be useful to cycle down (turn off)power hungry REHF displays. As such, cycling an REHF display may beautomated or user initiated without departing from the presentinvention. Thus, at a step 1002, the method determines whether autocycle is enabled. If the method determines at a step 1002 that autocycle is enabled, the method then determines whether a timer has beenexceeded at a step 1004. In some embodiments, a timer may be set to arange of approximately 1 to 10 seconds. In other embodiments, a timermay be set to more than 10 seconds. If the method determines at a step1004 that a timer has not been exceeded, then the method continues to astep 1006 to resume whereupon the method continues to a step 1004. Ifthe method determines at a step 1004 that a timer has been exceeded, themethod continues to a step 1010 to cycle down an REHF display. If themethod determines at a step 1002 that auto cycle is not enabled, themethod continues to a step 1008 to determine whether a user initiatedcycle down is requested. Cycling down may be user initiated in anynumber of manners well-known in the art without departing from thepresent invention. For example, in an embodiment, a cycle down buttonembodied in a physical or virtual interface may serve to provide cycledown input. If the method determines at a step 1008 that a userinitiated cycle down is not requested, the method continues to resume ata step 1006. If the method determines at a step 1008 that a userinitiated cycle down is requested, the method continues to a step 1010to cycle down a REHF display.

Once an REHF display is cycled down, a user may continue to view acomplementary BILF display. As noted above, some actions may requireapplication navigation features that are not available to a BILFdisplay. This is particularly true where a BILF display is not in amigrated mode. Migration is discussed in further detail above for FIG.2. When such an action occurs, then an REHF display may be cycled up. Assuch, at a step 1012, the method waits for a user event requiring acycle up of an REHF display. At a step 1014, the method determineswhether a user event requiring a cycle up of the REHF display hasoccurred. If the method determines at a step 1014 that a relevant userevent has occurred, the method continues to cycle up an REHF at a step1016 whereupon the method ends. If the method determines at a step 1014that a relevant user event has not occurred, the method returns to astep 1012 to wait for a relevant user event.

In some embodiments, wiping a display may be desirable. In exampleswhere sensitive information is being viewed, the ability to quickly wipea semi-permanent display such as a BILF EPD. Wiping may be userinitiated in any number of manners well-known in the art withoutdeparting from the present invention. For example, in an embodiment, awipe button embodied in a physical or virtual interface may serve toprovide wipe input. After a wipe, the BILF may be restored from anappropriate buffer.

In some embodiments, and BILF may be utilized to provide statusinformation. Status information typically does not require highfrequency refresh rates because the information displayed is read onlyand does not change at a high rate. Thus, status information may becontinuously displayed without unduly burdening power supplies. Thus,status information like: power information, network connectioninformation, signal strength information, user configurationinformation, display wakefulness information, date information, timeinformation, application information, and system information may bedisplayed on a BILF in some embodiments.

While this invention has been described in terms of several preferredembodiments, there are alterations, permutations, and equivalents, whichfall within the scope of this invention. It should also be noted thatthere are many alternative ways of implementing the methods andapparatuses of the present invention. Although various examples areprovided herein, it is intended that these examples be illustrative andnot limiting with respect to the invention. For example, in FIG. 1,steps 112, 114, and 116 are presented in a particular order. However, asmay be appreciated, those steps may be performed in any order withoutdeparting from the present invention. Indeed, any steps which may beperformed in any order are not intended to be limiting with respect tothe manner in which they are presented herein. Further, the Abstract isprovided herein for convenience and should not be employed to construeor limit the overall invention, which is expressed in the claims. It istherefore intended that the following appended claims be interpreted asincluding all such alterations, permutations, and equivalents as fallwithin the true spirit and scope of the present invention.

1. A method for controlling complementary dual displays of an electronicdevice, the method comprising: executing an application on theelectronic device, the application for viewing one or more pages ofinformation on the device; generating a video signal by the application,wherein the video signal is part of a user interface for interactingwith one or more pages of information displayed on the device; sendingthe video signal to a refresh-based high frame rate (REHF) display;displaying the video signal on the REHF display; generating a firstframe by the application, the first frame comprising at least a portionof a first page of information; writing the first frame to a framebuffer associated with a bistable low frame rate (BILF) display;displaying the first frame from the frame buffer on the BILF display;receiving a user selection via the user interface displayed on the REHFdisplay, the user selection to display an intermediate location withinthe first page of information currently displayed on the BILF display;generating a second frame based on the user selection, the second framedifferent from the first frame and comprising at least a portion of thefirst page of information corresponding to the intermediate location;writing the second frame to the frame buffer associated with the BILFdisplay; displaying the second frame from the frame buffer on the BILFdisplay; generating a second video signal by the application, whereinthe second video signal comprises a feedback signal to update the REHFdisplay and is generated based at least in part on the second frame, thefeedback signal indicative of the display of the second frame on theBILF display; and sending the second video signal to the REHF display toupdate the REHF display.
 2. The method of claim 1 wherein the secondvideo signal is sent over a wireless connection.
 3. The method of claim2 wherein the wireless connection is selected from the group consistingof: Bluetooth, 802.11a, 801.11b, 802.11g, 2.4 GHz wireless, IR wireless,and ultra wide band.
 4. The method of claim 1 wherein a first pluralityof commands from the application are accessed from the REHF display andthe BILF display.
 5. The method of claim 1 further comprising: on aclean command for the BILF display, refreshing a current frame such thatartifacts are reduced.
 6. The method of claim 5 further comprising:before the refreshing, clearing the current frame.
 7. The method ofclaim 5 wherein the clean command is configured to execute each time anew frame is displayed.
 8. The method of claim 1 further comprising: ona wipe command for the BILF display, wiping the BILF display such thatthe BILF display is blank.
 9. The method of claim 1 wherein the secondvideo signal includes status information.
 10. The method of claim 9wherein the status information is selected from the group consisting of:power information, network connection information, signal strengthinformation, user configuration information, display wakefulnessinformation, date information, time information, applicationinformation, and system information.
 11. The method of claim 1 whereinthe portion of the first plurality of commands is selected from thegroup consisting of: a migrate command, a pagination command, a zoomcommand, a session termination command, a search command, a clearcommand, and a display selection command.
 12. The method of claim 1wherein the application is controllable from the REHF display when theBILF display is connected with the electronic device.
 13. The method ofclaim 4 wherein the first application and the second application arecontrollable from the REHF display when the BILF display is connectedwith the electronic device.
 14. The method of claim 1 wherein the firstvideo signal is automatically converted to provide a best first displaycolor and a best first display resolution of the REHF display and thesecond video signal is automatically converted for a best second displaycolor and a best second display resolution of the BILF display.
 15. Themethod of claim 1 further comprising: cycling down the REHF display on acycle down command, wherein the cycle down command is in response to afirst user input; cycling down the REHF display after a cycle down timeinterval if the first input is not received within the cycle down timeinterval; and cycling up the REHF display on a cycle up command, whereinthe cycle up command is in response to a second user input.
 16. Themethod of claim 15 wherein the cycle down time interval is in a range ofapproximately 1 to 10 seconds.
 17. The method of claim 1, wherein thevideo signal displayed on the REHF display is part of a user interfacefor searching within one or more pages of information displayed on theBILF display, and wherein the user selection comprises a search query.18. The method of claim 17, further comprising, wherein the second framedisplayed on the BILF display comprises a page of information thatcontains an occurrence of the search query.
 19. The method of claim 1,wherein the video signal displayed on the REHF display is part of a userinterface for navigating one or more pages of information displayed onthe BILF display, and wherein the user selection comprises user input tonavigate to a different location within the one or more pages ofinformation.
 20. The method of claim 19, wherein the second framedisplayed on the BILF display comprises a page of information at thedifferent location specified by the user selection.
 21. The method ofclaim 19, wherein the interface for navigating the one or more pages ofinformation comprises a table of contents for the one or more pages ofinformation.
 22. An electronic device comprising: a refresh-based highframe rate (REHF) display; a bistable low frame rate (BILF) display; anda processor coupled to the REHF display and the BILF display, whereinthe processor is configured to: execute an application for viewing oneor more pages of information on the device, generate a video signalbased on instructions in the application, wherein the video signal ispart of a user interface for interacting with one or more pages ofinformation displayed on the device, send the video signal to the REHFdisplay, display the video signal on the REHF display, generate a firstframe based on instructions in the application, the first framecomprising at least a portion of a first page of information, write thefirst frame to a frame buffer associated with the BILF display, displaythe first frame from the frame buffer on the BILF display, receive auser selection via the user interface displayed on the REHF display, theuser selection to display an intermediate location within the first pageof information currently displayed on the BILF display, generate asecond frame based on the user selection, the second frame differentfrom the first frame and comprising at least a portion of the first pageof information corresponding to the intermediate location, write thesecond frame to the frame buffer associated with the BILF display,display the second frame from the frame buffer on the BILF display,generate a second video signal based on instructions in the application,wherein the second video signal comprises a feedback signal to updatethe REHF display and is generated based at least in part on the secondframe, the feedback signal indicative of the display of the second frameon the BILF display; and sending the second video signal to the REHFdisplay to update the REHF display.
 23. The electronic device of claim22, wherein the video signal is part of a user interface for searchingwithin one or more pages of information displayed on the BILF display,and wherein the user selection comprises a search query.
 24. Theelectronic device of claim 23, wherein the second frame comprises a pageof information that contains an occurrence of the search query.
 25. Theelectronic device of claim 22, wherein the video signal is part of auser interface for navigating one or more pages of information displayedon the BILF display, and wherein the user selection comprises user inputto navigate to a different location within the one or more pages ofinformation.
 26. The electronic device of claim 25, wherein the secondframe comprises a page of information at the different locationspecified by the user selection.
 27. The electronic device of claim 25,wherein the interface for navigating the one or more pages ofinformation comprises a table of contents for the one or more pages ofinformation.
 28. A computer program product for controllingcomplementary dual displays for use with an electronic device, thecomputer program product comprising a non-transitory computer-readablestorage medium containing computer program code for: generating a videosignal, wherein the video signal is part of a user interface forinteracting with one or more pages of information displayed on thedevice; sending the video signal to a refresh-based high frame rate(REHF) display, wherein the REHF display is configured to display thevideo signal; generating a first frame, the first frame comprising atleast a portion of a first page of information; writing the first frameto a frame buffer associated with a bistable low frame rate (BILF)display, wherein the BILF display is configured to display the firstframe from the frame buffer; receiving a user selection via the userinterface displayed on the REHF display, the user selection to displayan intermediate location within the first page of information currentlydisplayed on the BILF display; generating a second frame based on theuser selection, the second frame different from the first frame andcomprising at least a portion of the first page of informationcorresponding to the intermediate location; writing the second frame tothe frame buffer associated with the BILF display, wherein the BILFdisplay is configured to display the second frame from the frame buffer,generating a second video signal, wherein the second video signalcomprises a feedback signal to update the REHF display and is generatedbased at least in part on the second frame, the feedback signalindicative of the display of the second frame on the BILF display; andsending the second video signal to the REHF display to update the REHFdisplay.
 29. The computer program product of claim 28, wherein the videosignal is part of a user interface for searching within one or morepages of information displayed on the BILF display, and wherein the userselection comprises a search query.
 30. The computer program product ofclaim 29, wherein the second frame comprises a page of information thatcontains an occurrence of the search query.
 31. The computer programproduct of claim 28, wherein the video signal is part of a userinterface for navigating one or more pages of information displayed onthe BILF display, and wherein the user selection comprises user input tonavigate to a different location within the one or more pages ofinformation.
 32. The computer program product of claim 31, wherein thesecond frame comprises a page of information at the different locationspecified by the user selection.
 33. The computer program product ofclaim 31, wherein the interface for navigating the one or more pages ofinformation comprises a table of contents for the one or more pages ofinformation.